<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>01_页面版心</title>
    <style>
        .fu{
            background-color: lightgreen;
        }
        .zi{
            width: 1000px;
            background-color: pink;
            margin: auto;
            .d{
                width: 300px;
                height: 400px;
                border: 5px solid #000000;
                background-color: lightsalmon;
                text-align: center;
                line-height: 400px;
                margin: 0 auto;
            }
        }
    </style>
</head>
<body>
<div class="fu">
    <div class="zi">
        <div class="d">
        我是内容
        </div>
    </div>
</div>
</body>
</html>